The present invention relates to a bi-directional autonomous truck, particularly a dump truck for use in surface mining operations that is adapted for being driven in two opposite directions with substantially equal facility.
Mining operations typically employ very large dump trucks, e.g., having a capacity of hundreds of tons, for receiving excavated earth at a mining face or loading point, transporting the earth to a point of processing or deposit, dumping the earth, and returning to the loading point. As the technology has advanced, these trucks have more frequently been provided in so-called “autonomous,” form, meaning that they are remotely controlled; however, where such a truck would include a cabin for housing an operator, the cabin is typically biased toward one end of the truck, with the dump bed of the truck being biased toward the other end of the truck.
The trucks may be powered directly by a diesel or other combustion engine through a gear train, or by such an engine driving a generator for powering one or more electric motors located at respective wheels. For a truck powered directly by a combustion engine, a plurality of forward gears are provided in order to permit the engine to remain within an efficient range of engine speeds over a wide range of road speeds. On the other hand, backing-up is typically done at low speed, so that only a single reverse gear is provided for this purpose.
Where one or more wheels of the truck are powered by respective electric motors, the motors may be AC or DC. Analogous to the combustion engine, motor speed is varied in the forward directions by varying the current to or voltage across the motors, with a plurality of voltage or current settings which may be discrete or continuous, but motor speed is intentionally limited by a governing device in reverse.
In use, the truck is driven from point A to point B, where point A may be a loading point or source of earth that has been excavated and point B may be a location for depositing the excavated earth that is some distance away from point A. For traveling between points A and B, it is desirable to use the forward gears of the truck, so that the distance is traversed most efficiently. Accordingly, the truck must be turned around at each point. This may be done with the forward gears only, but at the expense of utilizing a relatively large amount of space corresponding to the turning circle of the truck. Typically, however, it is done by using the reverse gear, though this takes additional time and effort as well, and either option complicates the logistics of the mining operation where there are multiple instances of the truck operating in the same area.
Accordingly, there is a need for a bi-directional autonomous truck that provides substantially the same drive-characteristics in two opposite directions, to minimize or eliminate the need to turn the truck around.